Silvopasture and Agroforestry

Processing walnuts: removing the hulls

I’ve spoken before that a byproduct of processing walnuts can be used to tan animal hides. Walnut hulls are green when they fall from the tree and quickly turn black. Pulp in between the hull and nutshell as well as the hull itself all contain large amounts of tannic acid which is water soluble. Soaking hides with walnut hulls in water preserves the hides as well as providing dye of the beautiful deep brown common to all things walnut.

This is the step where nitrile gloves are required if you want to avoid tanning your own hide. Trust me on this, the dye cannot be removed and will persist until your skin naturally replaces itself. I tanned my own hands by using cotton work gloves that had been dipped in rubber. Clearly, they did not provide enough protection:



To loosen the hulls, I use an antique corn sheller. Other methods commonly used are: driving over intact fruit with a vehicle or more dangerously, setting a vehicle on blocks and spinning tires over walnuts; manual removal with a nut cracker or vise; another dangerous method is injecting compressed air via a needle into the hull.

I chose the corn sheller because it is pretty easy, my uncle has one, it is only moderately dangerous and plays into my love of antique machinery:


With my machine:

  • Load the hopper with intact nuts
  • Set buckets under the machine to catch hulls and another to catch dehulled nuts
  • Spin the handle to build up momentum in the gears
  • Let walnuts drop into the sheller one by one
    • Very frequently, I must turn the flywheel manually as the nut stops the motion and it is the only safe way to stick my hand into dangerous equipment to push the nut through
    • Every 5 gallon bucket, I use a screwdriver to reach in and clean the teeth of the sheller. With walnuts this fresh, they tend to clog the teeth with gunk.
  • Hand clean the remaining hulls from the nuts
    • put the hulls in a larger container for storage
    • do the same for finished nuts

A lot of people then wash the nuts with high pressure water. I just make an effort to move on to the next step soon after. That next step is cracking and extracting the edible meat of the nuts!

Silvopasture and Agroforestry

Harvesting the fruit of Juglans nigra, aka Black Walnut

Harvesting walnuts is a very easy process. The fruit will simply fall from the tree when it is ripe. Creepy crawlies that get into the fallen fruit before they can be gathered don’t penetrate the shell of the walnut, thus do not ruin the fruit. If those nuts gross you out, let them lie to nourish the wildlife!

Even in years where the trees produce only a modest yield, the ground beneath a mature walnut tree looks like a hastily abandoned tennis court…especially after windy days:


Luckily I have so many native mature trees that competition with squirrels is not an issue. Last week I was gathering nuts along side a fox squirrel that might have been bigger than my parents’ small breed dog.

Actual harvesting process:

  • Grab some containers keeping in mind that they WILL be dyed by the hulls of the walnuts
  • Similarly, grab a few pairs of nitrile gloves
  • Head out to a walnut tree and gather the fruit that has fallen

This year, my average time spent harvesting is filling a 5 gallon bucket in 7 minutes. I enjoy the workout of carrying 2 buckets at a time 100 or so yards back to the barn for storage/processing, but it does cause my arms, shoulders and trapezius muscles to burn intensely.


My favorite part about harvesting walnuts is that I get to directly observe the variations in tree genes. I have two trees that look like twins, but one produces walnuts that are so large (between a baseball and a softball) that they don’t feed well into the corn sheller I use to dehull the nuts. The other produces nuts that are close to a golf ball in size. So while harvesting walnuts, I can identify trees to propegate, or if I want ot get more involved in breeding, harvest pollen to be applied to another tree that produces large nuts.

The same information helps me identify trees to focus on human consumption, while the rest are perfect candidates under which to put hogs when they come to the farm!

Basically walnuts tap into my deepest levels of tree nerdom.